Timing disc fixing

ABSTRACT

The invention relates to a timing disc fitting for an encoder system. It consists of a timing disc hub ( 1 ) which can be plugged to a motor shaft ( 2 ) and to which there is fixed a timing disc ( 3 ). In accordance with the invention, the timing disc hub consists of a metallic heat-conducting material to which, on one side, a plastic insulating material is adhered. In the flange plane ( 1   a ) of the timing disc hub ( 1 ) there are arranged projections or lugs ( 5, 6, 7 ) which engage correspondingly shaped indentations, recesses or cut-outs ( 3   a,    3   b ) in the timing disc ( 3 ).

BACKGROUND OF THE INVENTION

The invention relates to a timing disc fitting for encoder systems, consisting of the timing disc, a timing disc hub and optionally further fitting means such as glued, threaded or clamped connections.

SUMMARY OF THE INVENTION

In accordance with the invention, the objective is achieved by the characteristics listed in the claims. It has been found that a timing disc consisting of a metallic plate coated with a plastic insulating material on one side permits a high degree of heat discharge, wherein, as a result of the mechanical clamping condition, a clearance-free transmission of changing torque values is guaranteed, even under the influence of varying temperatures.

Below, the invention will be explained in greater detail with reference to several embodiments.

THE DRAWINGS

FIG. 1 shows the inventive timing disc fitting in an encoder system;

FIG. 2 is an enlarged partial section of the region of the timing disc fitting according to a first embodiment of the invention;

FIG. 3 shows the inventive timing disc fitting of the second embodiment in an exploded view (unjoined) according to a second embodiment of the invention;

FIG. 4 shows the inventive timing disc fitting of the second embodiment in a front view (joined);

FIG. 5 is a cross-section through the inventive timing disc fitting (joined) of the second embodiment; and

FIG. 6 shows the inventive timing disc fitting of the second embodiment in a rear view (joined).

DETAILED DESCRIPTION

FIG. 1 shows the timing disc hub 1 on the motor shaft 2 of a motor 8 in a mounted condition. During the rotational movement of the motor shaft 2, the timing disc 3 is carried along and rotates in the gap of a C-shaped motor sensor component 9 which is secured to a PCB conductor plate 10.

In the enlarged partial section (FIG. 2) it is possible to see the design principle of the inventive timing disc fitting. The timing disc hub is slipped on to the motor shaft 2 with no clearance and joined to timing disc 3 by recesses 3 a, 3 b, 3 c. The fitting is of the form-fitting type and is effected by projections in the form of lugs 5 a, 5 b, with a plastic insulating material 4A being arranged between the timing disc hub 1 and the timing disc 3.

FIG. 3 shows a second embodiment of the timing disc hub 1 and the timing disc 3 prior to being joined. The lugs 5, 6, 7 at the timing disc hub 1 are aligned in such a way that they can be introduced into the respective bores 3 a, 3 b, 3 c of the timing disc 3.

After the timing disc hub 1 and the timing disc 3 have been joined, the lugs 5, 6, 7 are positioned so that the hub and disc can be clamped together. This position is shown in FIG. 4, with the timing disc 3 in its joined condition being visible in a front view.

FIG. 5 shows the structure after joining and after the lug 5 has been bent. In this way, the timing disc hub 1 and the timing disc 3 are secured in a clearance-free and permanent way. In the cross-sectional illustration of FIG. 5 it can be seen that the timing disc 1 is coated with a plastic insulating material 4. The plastic coating on one side ensures that the heat flow from the encoder end is discharged via the motor shaft, but because of the insulating effect of the plastic coating, the timing disc 3 is thermally isolated from the disc hub and motor shaft. Thus, the discharge of heat does not affect the accuracy of the timing disc.

FIG. 6 shows the inventive timing disc fitting in a rear view, with the timing disc hub 1 being permanently connected to the timing disc 3 via the bent lugs 5, 6, 7. 

1. A timing disc fitting for an encoder system, comprising a timing disc hub (1) which can be plugged to a motor shaft (2) and a timing disc (3) fixed to said timing disc hub and including a plurality of recesses (3 a, 3 b), said timing disc hub comprising a metallic heat conducting material and a plastic insulating material (4) adhered to one side of said timing disc, said timing disc hub including projections (5, 6, 7) which engage correspondingly recesses (3 a, 3 b) in the timing disc (3).
 2. A timing disc fitting according to claim 1, wherein the plastic insulating material (4) is arranged on the side (1 b) of the timing disc hub (1) which faces the timing disc (3).
 3. A timing disc fitting according to claim 1, wherein the plastic insulating material is a film, a foil or a paint.
 4. A timing disc fitting according to claim 3, wherein the plastic insulating material is self-adhesive.
 5. A timing disc fitting according to claim 1, wherein the projections (5, 6, 7) are in the form of hooks, knobs, lugs or bent metal strips. 